OpenRAM/README.md

# OpenRAM
[![pipeline status](https://scone.soe.ucsc.edu:8888/mrg/PrivateRAM/badges/dev/pipeline.svg)](https://scone.soe.ucsc.edu:8888/mrg/PrivateRAM/commits/dev)
[![License: BSD 3-clause](./image/license_badge.svg)](./LICENSE)

An open-source static random access memory (SRAM) compiler.

# Why OpenRAM?


# Basic Setup

The OpenRAM compiler has very few dependencies:
+ ngspice-26 (or later) or HSpice I-2013.12-1 (or later) or CustomSim 2017 (or later)
+ Python 3.5 and higher
+ Python numpy (pip3 install numpy to install)
+ flask_table (pip3 install flask to install)
+ a setup script for each technology you want to use
+ a technology directory for each technology with the base cells (comes with [SCMOS][SCMOS] and [FreePDK45][FreePDK45])

If you want to perform DRC and LVS, you will need either:
+ Calibre (for [FreePDK45][FreePDK45] or [SCMOS][SCMOS])
+ Magic + Netgen (for [SCMOS][SCMOS] only)

You must set two environment variables: OPENRAM\_HOME should point to
the compiler source directory. OPENERAM\_TECH should point to a root
technology directory that contains subdirs of all other technologies.
For example, in bash, add to your .bashrc:
```
  export OPENRAM_HOME="$HOME/openram/compiler"
  export OPENRAM_TECH="$HOME/openram/technology"
```
For example, in csh/tcsh, add to your .cshrc/.tcshrc:
```
  setenv OPENRAM_HOME "$HOME/openram/compiler"
  setenv OPENRAM_TECH "$HOME/openram/technology"
```

We include the tech files necessary for FreePDK and [SCMOS][SCMOS]. The [SCMOS][SCMOS]
spice models, however, are generic and should be replaced with foundry 
models.
If you are using FreePDK, you should also have that set up and have the
environment variable point to the PDK. 
For example, in bash, add to your .bashrc:
```
  export FREEPDK45="/bsoe/software/design-kits/FreePDK45"
```
For example, in csh/tcsh, add to your .tcshrc:
```
  setenv FREEPDK45 "/bsoe/software/design-kits/FreePDK45"
```
We do not distribute the PDK, but you may download [FreePDK45][FreePDK45]

If you are using [SCMOS][SCMOS], you should install [Magic][Magic] and [Netgen][Netgen].
We have included the SCN4M design rules from [Qflow][Qflow].

# Directory Structure

* compiler - openram compiler itself (pointed to by OPENRAM_HOME)
  * compiler/base - base data structure modules
  * compiler/pgates - parameterized cells (e.g. logic gates)
  * compiler/bitcells - various bitcell styles
  * compiler/modules - high-level modules (e.g. decoders, etc.)
  * compiler/verify - DRC and LVS verification wrappers
  * compiler/characterizer - timing characterization code
  * compiler/gdsMill - GDSII reader/writer
  * compiler/router - router for signals and power supplies
  * compiler/tests - unit tests
* technology - openram technology directory (pointed to by OPENRAM_TECH)
  * technology/freepdk45 - example configuration library for freepdk45 technology node
  * technology/scn4m_subm - example configuration library [SCMOS][SCMOS] technology node
  * technology/scn3me_subm - unsupported configuration (not enough metal layers)
  * technology/setup_scripts - setup scripts to customize your PDKs and OpenRAM technologies
* docs - LaTeX manual (outdated)
* lib - IP library of pregenerated memories


# Unit Tests

Regression testing  performs a number of tests for all modules in OpenRAM.

Use the command:
```
   python regress.py
```
To run a specific test:
```
   python {unit test}.py 
```
The unit tests take the same arguments as openram.py itself. 

To increase the verbosity of the test, add one (or more) -v options:
```
   python tests/00_code_format_check_test.py -v -t freepdk45
```
To specify a particular technology use "-t <techname>" such as
"-t freepdk45" or "-t scn4m\_subm". The default for a unit test is scn4m_subm. 
The default for openram.py is specified in the configuration file.


# Creating Custom Technologies

All setup scripts should be in the setup\_scripts directory under the
$OPENRAM\_TECH directory.  Please look at the following file for an
example of what is needed for OpenRAM:
```
  $OPENRAM_TECH/setup_scripts/setup_openram_freepdk45.py
```
Each setup script should be named as: setup\_openram\_{tech name}.py.

Each specific technology (e.g., freepdk45) should be a subdirectory
(e.g., $OPENRAM_TECH/freepdk45) and include certain folders and files:
  1. gds_lib folder with all the .gds (premade) library cells. At a
     minimum this includes:
     * ms_flop.gds
     * sense_amp.gds
     * write_driver.gds
     * cell_6t.gds
     * replica_cell_6t.gds 
     * tri_gate.gds
  2. sp_lib folder with all the .sp (premade) library netlists for the above cells.
  3. layers.map 
  4. A valid tech Python module (tech directory with __init__.py and tech.py) with:
     * References in tech.py to spice models
     * DRC/LVS rules needed for dynamic cells and routing
     * Layer information
     * etc.

# License 

OpenRAM is licensed under the [BSD 3-clause License](./LICENSE).

# Contributors & Acknowledgment

- [Matthew Guthaus][Matthew Guthaus] created the OpenRAM project and is the lead architect.


* * *

[Matthew Guthaus]:       https://users.soe.ucsc.edu/~mrg
[Github releases]:       https://github.com/PrivateRAM/PrivateRAM/releases
[Github issues]:         https://github.com/PrivateRAM/PrivateRAM/issues
[Github pull requests]:  https://github.com/PrivateRAM/PrivateRAM/pulls
[Github projects]:       https://github.com/PrivateRAM/PrivateRAM/projects
[Github insights]:       https://github.com/PrivateRAM/PrivateRAM/pulse
[email me]:              mailto:mrg+openram@ucsc.edu
[VLSIDA]:                https://vlsida.soe.ucsc.edu
[OSUPDK]:                https://vlsiarch.ecen.okstate.edu/flow/
[Magic]:                 http://opencircuitdesign.com/magic/
[Netgen]:                http://opencircuitdesign.com/netgen/
[Qflow]:                 http://opencircuitdesign.com/qflow/history.html
[FreePDK45]:             https://www.eda.ncsu.edu/wiki/FreePDK45:Contents
[SCMOS]:                 https://www.mosis.com/files/scmos/scmos.pdf